U.S. patent application number 10/488190 was filed with the patent office on 2004-12-02 for method for the production of a polymer conversion product by means of metal catalysis.
Invention is credited to Heischkel, Yvonne, Jordan, Rainer, Nuyken, Oskar, Stockel, Nicolas.
Application Number | 20040242816 10/488190 |
Document ID | / |
Family ID | 7697401 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040242816 |
Kind Code |
A1 |
Heischkel, Yvonne ; et
al. |
December 2, 2004 |
Method for the production of a polymer conversion product by means
of metal catalysis
Abstract
In a process for polmerizing a mixture comprising at least one
free-radically polymerizable monomer and a transition metal complex
whose transition metal is capable of reversibly binding a halogen
atom, thus bringing about a change in the oxidation state of the
transition metal from a first oxidation state to a second, in the
presence of an initiator R-Y, where Y is halogen and R is alkyl,
substituted alkyl, cycloalkyl (substituted or unsubstituted), aryl
or --CH.sub.nHal.sub.3-n, where n=0 to 2 and Hal=halogen, in an
aqueous system, the transition metal is bound via suitable anchor
groups to the hydrophobic part of an amphiphilic polymer which is
made up of a hydrophilic part and a hydrophobic part. Also provided
are a corresponding transition metal complex, a reaction product
which can be prepared by this process and the use of this
transition metal complex for preparing reaction products by
free-radical polymerization.
Inventors: |
Heischkel, Yvonne;
(Mannheim, DE) ; Stockel, Nicolas; (Munchen,
DE) ; Nuyken, Oskar; (Munchen, DE) ; Jordan,
Rainer; (Muenchen, DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
7697401 |
Appl. No.: |
10/488190 |
Filed: |
March 1, 2004 |
PCT Filed: |
August 23, 2002 |
PCT NO: |
PCT/EP02/09469 |
Current U.S.
Class: |
526/171 ;
526/303.1; 526/317.1; 526/319; 526/335; 526/341; 526/346 |
Current CPC
Class: |
C08F 4/00 20130101 |
Class at
Publication: |
526/171 ;
526/303.1; 526/346; 526/317.1; 526/319; 526/335; 526/341 |
International
Class: |
C08F 004/80 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 2001 |
DE |
101 42 908.8 |
Claims
We claim:
1. A process for polymerizing a mixture comprising at least one
free-radically polymerizable monomer and a transition metal complex
whose transition metal is capable of reversibly binding a halogen
atom, thus bringing about a change in the oxidation state of the
transition metal from a first oxidation state to a second, in the
presence of an initiator R-Y, where Y is halogen and R is alkyl,
substituted alkyl, cycloalkyl (substituted or unsubstituted), aryl
or --CH.sub.nHal.sub.3-n, where n=0 to 2 and Hal=halogen, in an
aqueous system, wherein the transition metal is bound via suitable
anchor groups to the hydrophobic part of an amphiphilic polymer
which is made up of a hydrophilic part and a hydrophobic part.
2. A process as claimed in claim 1, wherein the amphiphilic polymer
is selected from among lipids, polyoxazolines, polyglycols,
poly(meth)acrylamides and polyurethanes whose hydrophobic parts in
each case have suitable anchor groups for binding the transition
metal.
3. A process as claimed in claim 1 or 2, wherein the transition
metal is selected from among Ru.sup.2+, Ru.sup.3+, Mn.sup.3+,
Mn.sup.4+, Cu.sup.+, Cu.sup.2+, Ni.sup.0, Ni.sup.+, Fe.sup.2+ and
Fe.sup.3+.
4. A process as claimed in any of claims 1 to 3, wherein the anchor
groups are preferably selected from among diphenylphosphine
radicals in which the phenyl groups can be substituted or
unsubstituted, pyridyl radicals which can be substituted or
unsubstituted, in particular bipyridyl radicals which are linked to
the polymer via one of the pyridyl groups, pyrrole radicals which
can be substituted or unsubstituted, in particular bipyrrole
radicals which are linked to the polymer via one of the pyrrole
groups, and cyclopentadienyl radicals which may, if desired, be
substituted in addition to the bond to the polymer.
5. A process as claimed in any of claims 1 to 4, wherein the
transition metal complex has the formula (III)
ML.sup.PL.sub.nX.sub.m (III) where the symbols have the following
meanings: M is a transition metal selected from among Ru.sup.2+,
Ru.sup.3+, Mn.sup.3+, Mn.sup.4+, Cu.sup.+, Cu.sup.2+, Ni.sup.0,
Ni.sup.+, Fe.sup.2+ and Fe.sup.3+; L.sup.P is an amphiphilic
polymer having suitable anchor groups for binding the transition
metal; L is a further ligand selected from among
triphenylphosphine, in which the phenyl groups may be substituted
or unsubstituted, substituted or unsubstituted pyridines,
substituted or unsubstituted pyrroles; X is a halide or a
C.sub.1-5-alkoxy group or C.sub.1-5-alkyl group; particularly
preferably chloride or bromide; n is an integer from 0 to 4,
preferably from 0 to 2; m is from 0 to 4, preferably from 0 to 3,
depending on the valence of the metal in the first oxidation
state.
6. A process as claimed in any of claims 1 to 5, wherein the
free-radically polymerizable monomer or monomers is/are selected
from the group consisting of: styrene compounds of the formula (IV)
3where R' and R" are each, independently of one another, H or
C.sub.1-C.sub.8-alkyl and n is 0, 1, 2 or 3; acrylic acid and
methacrylic acid and C.sub.1-C.sub.20-alkyl esters and
C.sub.1-C.sub.100-alkyloxy esters thereof; dienes having conjugated
double bonds; ethylenically unsaturated dicarboxylic acids and
derivatives thereof; N-vinyl compounds; and ethylenically
unsaturated nitrile compounds.
7. A process as claimed in any of claims 1 to 6, wherein the
initiator R-Y is selected from among ethyl 2-bromoisobutyrate,
1-phenylethyl bromide, 1-phenylethyl chloride, p-toluenesulfonyl
chloride, benzylhydryl chloride, 1,1,1-trichloroacetone,
.alpha.,.alpha.-dichloroacetophenone, bromotrichloromethane and
carbon tetrachloride.
8. A process as claimed in any of claims 1 to 7, wherein the
mixture further comprises, in addition to the transition metal
complex, the initiator and the free-radically polymerizable
monomer, a cocatalyst in the form of a Lewis acid.
9. A process as claimed in any of claims 1 to 8 carried out in a
temperature range from 20 to 140.degree. C.
10. A transition metal complex of the formula (III)
ML.sup.PL.sub.nX.sub.m (III) where the symbols have the following
meanings: M is a transition metal selected from among Ru.sup.2+,
Ru.sup.3+, Mn.sup.3+, Mn.sup.4+, Cu.sup.+, Cu.sup.2+, Ni.sup.0,
Ni.sup.+, Fe.sup.2+ and Fe.sup.3+; L.sup.P is an amphiphilic
polymer having suitable anchor groups for binding the transition
metal; L is a further ligand selected from among
triphenylphosphine, in which the phenyl groups may be substituted
or unsubstituted, substituted or unsubstituted pyridines,
substituted or unsubstituted pyrroles; X is a halide or a
C.sub.1-5-alkoxy group or C.sub.1-5-alkyl group; particularly
preferably chloride or bromide; n is an integer from 0 to 4,
preferably from 0 to 2; m is from 0 to 4, preferably from 0 to 3,
depending on the valence of the metal in the first oxidation
state.
11. A reaction product which can be prepared by means of a process
as claimed in any of claims 1 to 9.
12. The use of transition metal complexes comprising an amphiphilic
polymer which is made up of a hydrophilic part and a hydrophobic
part and to whose hydrophobic part transition metals, which may
optionally bear further ligands, are bound via suitable anchor
groups in a process for preparing a reaction product under
free-radical conditions in the presence of at least one
free-radically polymerizable monomer in an aqueous system.
Description
[0001] The present invention relates to a process for polymerizing
a mixture comprising at least one free-radically polymerizable
monomer and a transition metal complex whose transition metal is
capable of reversibly binding a halogen atom, thus bringing about a
change in the oxidation state of the transition metal from a first
oxidation state to a second, in the presence of an initiator R-Y,
where Y is halogen and R is alkyl, substituted alkyl, cycloalkyl
(substituted or unsubstituted), aryl or --CH.sub.nHal.sub.3-n,
where n=0 to 2 and Hal=halogen. The invention further relates to
the corresponding transition metal complex, to a reaction product
which can be prepared by the process of the present invention and
to the use of the transition metal complex of the present invention
for preparing reaction products by free-radical polymerization.
[0002] The present invention is in the technical field of
free-radical polymerization having features which are typical of a
living polymerization system, and the process of the present
invention is in principle able to provide reaction products or
polymers which can have a narrow molecular weight distribution
(M.sub.w/M.sub.n). Furthermore, choice of appropriate monomers and,
if desired, successive addition of different monomers make it
possible to prepare both unbranched and branched homopolymers and
copolymers and also block copolymers.
[0003] For some years there has been great interest in processes or
process concepts which are suitable for preparing many polymers and
make it possible to produce such polymers having a predetermined
structure, molecular weight and molecular weight distribution.
[0004] One process concept by means of which such polymers having a
predetermined structure, molecular weight and molecular weight
distribution can be obtained is atom transfer radical
polymerization (ATRP). This is a controlled "living" free-radical
polymerization. ATRP can be catalyzed by suitable metal complexes.
In ATRP catalyzed by metal complexes the polymerization is
initiated by, for example, abstraction of a halogen atom from an
alkyl halide used as ATRP initiator by the metal complex, forming a
free alkyl radical. The alkyl radical subsequently adds onto a
free-radically polymerizable monomer in a chain reaction which can
be terminated by addition of the halogen atom abstracted by the
metal complex (back) onto the living polymer chain. Subsequent
renewed abstraction of the halogen atom from the polymer chain
makes a further monomer addition possible. This controlled
polymerization allows halogen-terminated polymers having a narrow
molecular weight distribution to be obtained. The molecular weight
is dependent on the initiator concentration.
[0005] WO 98/01480 relates, to the synthesis of homopolymers, block
copolymers or graft copolymers in which at least one polar group is
present and which have a defined structure and a narrow molecular
weight distribution by means of ATRP. Here, at least one
free-radically polymerizable monomer is reacted with a system
comprising a macroinitiator which contains at least one group which
can be transferred to form a free radical, a transition metal
complex and at least one ligand which coordinates via a .sigma. or
.pi. bond to the transition metal. The reaction is carried out in
bulk or in an organic solvent. However, the process proceeds at
polymerization rates which are unattractive for commercial use.
[0006] WO 00/47634 describes a process for preparing an acrylic
polymer by ATRP in an organic solvent such as ethyl acetate or
o-xylene, in which at least one vinylic monomer is reacted with a
suitable transition metal complex and an alkyl halide as initiator.
According to WO 00/47634, the reaction rate of the polymerization
process is increased by addition of a Lewis acid which is soluble
in the reaction mixture.
[0007] WO 97/18247 discloses an ATRP process in which the
polymerization of free-radically polymerizable monomers is carried
out in the presence of an initiator, a transition metal compound
and an amount of the conjugate oxidized form of the transition
metal compound which is sufficient to deactivate at least part of
the free radical initially formed in the polymerization. The
polymerization can be carried out in an aqueous medium using
monomers which are at least partly soluble in water or using
monomers suitable for an emulsion polymerization when the
polymerization is carried out in the presence of an emulsifier.
[0008] T. Makino et al. Polym. Prep. (Am. Chem. Soc., Div. Polym.
Chem.) 39, 288 (1998) disclose an ATRP of methyl methacrylate (MMA)
in an aqueous medium under emulsion polymerization conditions. The
catalyst used is a copper catalyst (CuBr+bipyridyl), the initiator
used is, for example, ethyl 2-bromoisobutyrate and the emulsifier
used is dodecyl sulfate. However, the reaction time is long. After
2 hours at 80.degree. C., PMMA is obtained in a yield of
80-90%.
[0009] T. Nishikawa et al. Macromolecules 32, 2204 (1999) describe
the living free-radical suspension polymerization of methyl
methacrylate (MMA) in the presence of PhCOCHCl.sub.2 or CCl.sub.3Br
as initiator, the transition metal complex
RuCl.sub.2(PPh.sub.3).sub.3 and optionally Al(O.sup.iPr).sub.3 in
an aqueous medium. Although the suspension polymerization is faster
than the corresponding polymerization in toluene, the reaction time
disclosed in FIG. 1 in T. Nishikawa et al. is nevertheless long.
After about 5 hours, the conversion (at a polymerization
temperature of 80.degree. C.) is only about 75%. A
close-to-complete conversion is achieved only after about 18
hours.
[0010] It is an object of the present invention to provide a novel
process for preparing a polymeric reaction product, which process
leads in a simple and controlled manner to homopolymers and
copolymers which can be prepared by a free-radical mechanism. Even
at low temperatures, it should be possible to achieve a reaction
rate which makes the process attractive for commercial use, i.e.
complete conversion of the monomers is achieved after comparatively
short reaction times. A further object of the invention is to
provide a process by means of which it is possible to prepare block
copolymers which cannot be obtained in other ways or can be
obtained only in an unsatisfactory manner in other ways.
[0011] The achievement of this object starts out from a process for
polymerizing a mixture comprising at least one free-radically
polymerizable monomer and a transition metal complex whose
transition metal is capable of reversibly binding a halogen atom,
thus bringing about a change in the oxidation state of the
transition metal from a first oxidation state to a second, in the
presence of an initiator R-Y, where Y is halogen or alkoxy and R is
alkyl, substituted alkyl, cycloalkyl (substituted or
unsubstituted), aryl or --CH.sub.nHal.sub.3-n, where n=0 to 2 and
Hal=halogen, in an aqueous system.
[0012] In the process of the present invention, the transition
metal is bound via suitable anchor groups to the hydrophobic part
of an amphiphilic polymer which is made up of a hydrophilic part
and a hydrophobic part.
[0013] In the aqueous system, the amphiphilic polymer forms
micelles which are functionalized with the transition metal complex
which serves as ATRP catalyst. Since only the hydrophobic part of
the amphiphilic polymer is functionalized with the ATRP catalyst,
the controlled free-radical polymerization occurs exclusively in
the micelles. This novel polymerization process achieves complete
monomer conversions at significantly lower polymerization
temperatures and significantly shorter polymerization times than in
the processes of the prior art. Such an increase in the reaction
rate makes it possible for the controlled free-radical
polymerization (ATRP) to be carried out economically.
[0014] For the purposes of the present invention, the term
"reaction product" encompasses both oligomers having a mean
molecular weight (M.sub.n) of at least 300 g/mol and polymers. The
mean molecular weight (M.sub.n) is thus generally from 300 to 5 000
000 g/mol, preferably from 500 to 2 000 000 g/mol, particularly
preferably from 500 to 1 000 000 g/mol. The molecular weights are
determined by GPC in THF using a polystyrene standard.
[0015] Although there are no restrictions in respect of the
molecular weight distribution, the process of the present invention
makes it possible to obtain a reaction product which has a
molecular weight distribution M.sub.w/M.sub.n measured by gel
permeation chromatography using polystyrene as standard
of.ltoreq.4, preferably.ltoreq.3, more preferably.ltoreq.2, in
particular.ltoreq.1.5 and in some cases even.ltoreq.1.3. The
molecular weights of the reaction product (A) can be controlled
within wide limits by choice of the ratio of monomers (a) to the
free-radical initiator.
[0016] Depending on the way in which the reaction is carried out,
the process of the present invention makes it possible to prepare
polymers, homopolymers, block or multiblock and gradated
(co)polymers, star-shaped polymers, graft copolymers and branched
(co)polymers functionalized at the end groups. Furthermore, the
reaction product prepared by the process of the present invention
can be used as a macroinitiator. In the present context, a
macroinitiator is an oligomeric or polymeric compound which has one
or more active sites which enable it to be used as initiator in
further free-radical polymerization processes. These further
free-radical polymerization processes can be any processes known to
those skilled in the art for free-radical polymerization and are
not restricted to the process of the present invention.
[0017] In a preferred embodiment, the present invention provides a
process for preparing a polymeric reaction product which is a
macroinitiator or a block copolymer.
[0018] For the purposes of the present invention, a "block
copolymer" is a polymer made up of at least two polymer blocks
having a different monomer composition. The expression "polymer
blocks having a different monomer composition" means, for the
purposes of the present invention, that at least two regions of the
block copolymer have at least two blocks having a different monomer
composition. For the purposes of the present invention, it is
possible for the transition between two blocks to be continuous,
i.e. for two blocks to be separated by a zone which has a random or
regular sequence of the monomers constituting the blocks. However,
it is likewise possible in the context of the present invention for
the transition between two blocks to be virtually discontinuous. In
the present context, a "virtually discontinuous transition" is a
transition zone which has a significantly shorter length than at
least one of the blocks separated by the transition zone. In a
preferred embodiment of the present invention, the chain length of
such a transition zone is less than {fraction (1/10)}, preferably
less than {fraction (1/20)}, of the block length of at least one of
the blocks separated by the transition zone.
[0019] For the purposes of the present invention, the expression
"different monomer composition" means that the monomers
constituting the respective block differ in at least one feature,
for example in the way they are linked to one another, in their
conformation or in their constitution. In the process of the
present invention, preference is given to preparing block
copolymers which have at least two blocks whose monomer composition
differs at least in the constitution of the monomers.
[0020] For the purposes of the present invention, an aqueous system
is a reaction medium which forms a single phase without a
macroscopic phase boundary and comprises from 80 to 100% by weight,
preferably from 90 to 100% by weight, particularly preferably from
95 to 100% by weight, of water. If the proportion of water is less
than 100% by weight, the aqueous system is a mixture of water and
one or more water-miscible solvents such as tetrahydrofuran,
methanol, ethanol, propanol, butanol, acetone, N-methylpyrrolidone
or methyl ethyl ketone.
[0021] For the purposes of the present invention, the term "alkyl"
refers to both branched and unbranched alkyl radicals (with the
exception of C.sub.1- and C.sub.2-alkyl groups).
[0022] The expression "aryl" employed below refers, for the
purposes of the present invention, to phenyl, naphthyl,
phenanthryl, anthracenyl, triphenylenyl, fluoroanthenyl, preferably
phenyl and naphthyl, in which each hydrogen atom can be replaced by
C.sub.1-20-alkyl, preferably C.sub.1-6-alkyl, particularly
preferably methyl, and each hydrogen atom in the respective alkyl
radical can in turn be replaced, independently of one another, by a
halogen atom, preferably fluorine or chlorine; furthermore, each
hydrogen atom in the respective aryl radical can be replaced by
C.sub.2-20-alkenyl, C.sub.2-20-alkynyl, C.sub.1-6-alkoxy,
C.sub.1-6-alkylthio, C.sub.3-8-cycloalkyl, phenyl, phenyl
substituted by 1-5 halogen atoms and/or from 1 to 5 C.sub.1-4-alkyl
radicals, halogen, primary or secondary amino groups. When aryl is
phenyl, the phenyl radical can be substituted by from 1 to 5 of the
radicals mentioned; when aryl is naphthyl, the naphthyl radical can
be substituted by from 1 to 7 of the radicals mentioned. Both
phenyl and naphthyl are, if they are substituted at all, preferably
substituted by from 1 to 3 substituents. Aryl is preferably phenyl,
phenyl substituted by from 1 to 5 fluorine or chlorine atoms,
phenyl substituted by from 1 to 3 C.sub.1-6-alkyl radicals or from
1 to 3 C.sub.1-4-alkoxy radicals or from 1 to 3 phenyl radicals.
Aryl is particularly preferably phenyl or tolyl.
[0023] The amphiphilic polymer (L.sup.P) can generally be any
polymer whose hydrophobic part has suitable anchor groups for
binding the transition metal complex. Preferred amphiphilic
polymers are those selected from among lipids, e.g.
phosphoglycerides or glycolipids, polyoxazolines, polyglycols, e.g.
polyethylene glycols or polypropylene glycols,
poly(meth)acrylamides and polyurethanes whose hydrophobic parts in
each case have suitable anchor groups for binding the transition
metal. Particular preference is given to polyoxazolines.
[0024] The preparation of the suitable amphiphilic polymers is
carried out by methods known to those skilled in the art, for
example polycondensation, living cationic polymerization, anionic
polymerization or controlled free-radical polymerization or other
polymerization techniques, using appropriately functionalized
monomers.
[0025] Suitable anchor groups for the transition metal complex are
dependent, inter alia, on the transition metal M used. In the ATRP
process, the transition metal complex repeatedly participates in a
reversible redox cycle with the initiator and/or the nonliving
halogen-terminated end of the polymer and the corresponding free
radical formed at one or more growing end(s) of the polymer.
Suitable transition metal compounds are thus all transition metal
compounds which can participate in this redox cycle with the
initiator and/or the nonliving end of the polymer but do not form a
direct carbon-metal bond with the polymer chain. Preferred
transition metals M are selected from among Ru.sup.2+, Ru.sup.3+,
Cu.sup.+, Cu.sup.2+, Fe.sup.2+, Fe.sup.3+, Cr.sup.2+, Cr.sup.3+,
Mo.sup.0, Mo.sup.+, Mo.sup.2+, Mo.sup.3+, W.sup.2+, W.sup.3+,
Rh.sup.3+, Rh.sup.4+, Co.sup.+, Co.sup.2+, Re.sup.2+, Re.sup.3+,
Ni.sup.0, Ni.sup.+, Mn.sup.3+, Mn.sup.4+, V.sup.2+, V.sup.3+,
Zn.sup.+, Zn.sup.2+, Au.sup.+, Au.sup.2+, Ag.sup.+ and Ag.sup.2+.
Particular preference is given to transition metals selected from
among Ru.sup.2+, Ru.sup.3+, Mn.sup.3+, Mn.sup.4+, Cu.sup.+,
Cu.sup.2+, Ni.sup.0, Ni.sup.+, Fe.sup.2+ and Fe.sup.3+. Very
particular preference is given to Ru.sup.2+ and Ru.sup.3+.
[0026] Suitable anchor groups are in principle groups which contain
at least one nitrogen, oxygen, phosphorus and/or sulfur atom which
can coordinate to the transition metal via a .sigma. bond and also
groups containing two or more carbon atoms which can coordinate to
the transition metal via a .pi. bond. Preference is given to groups
of the following formulae, which are generally bound to the polymer
via a single bond, a C.sub.2-8-alkylene group, an ether, ester or
amide function or via another group suitable for coupling the
anchor group to the polymer:
-Z'-R.sup.1 (I)
-Z'-(R.sup.2-Z').sub.m-R.sup.1 (II)
[0027] where
[0028] R.sup.1 is hydrogen, C.sub.1-20-alkyl, aryl, a heterocyclic
compound, C.sub.1-6-alkyl which bears a C.sub.1-6-alkoxy,
C.sub.1-4-dialkylamino, C(.dbd.Y)R.sup.3 or C(.dbd.Y)R.sup.4R.sup.5
substituent, or QC(.dbd.Y)R.sup.6, where Q is NR.sup.5 or
(preferably) O and R.sup.3 is C.sub.1-20-alkyl, C.sub.1-20-alkoxy,
aryloxy or a heterocyclic radical, R.sup.4 and R.sup.5 are each,
independently of one another, hydrogen or C.sub.1-20-alkyl, or
R.sup.4 and R.sup.5 together form an alkylene group having from 2
to 5 carbon atoms so that a 3- to 6-membered ring is formed, and
R.sup.6 is hydrogen, C.sub.1-20-alkyl or aryl;
[0029] Z' is O, S, NR.sup.7, PR.sup.7, where R.sup.7 is selected
from the same group as R.sup.1;
[0030] R.sup.2 is in each case a divalent group selected from among
C.sub.2-4-alkylene and C.sub.2-4-alkenylene, in which the covalent
bonds to the respective Z' are in vicinal positions or in
.beta.-positions, and C.sub.3-8-cycloalkanediyl,
C.sub.3-8-cycloalkenediyl, aryldiyl and heterocyclic diyl
compounds, where the covalent bonds to the respective Z' are in
vicinal positions;
[0031] m is from 1 to 6.
[0032] Further suitable anchor groups are cyclic or heterocyclic
compounds which may be aromatic or aliphatic. These are generally
bound to the polymer via a single bond, a C.sub.2-8-alkylene group,
an ether, ester or amide function or via another group which is
suitable for coupling the anchor group to the polymer. Condensed
systems such as indenyl derivatives or fluorenyl derivatives are
also suitable. Preferred carbocyclic anchor groups are aryl or
cyclopentadienyl groups, particularly preferably cyclopentadienyl
groups which may, if desired, be substituted in addition to the
bond to the polymer. Suitable substituents are C.sub.1-6-alkyl,
C.sub.3-8-cycloalkyl, C.sub.2-6-alkenyl, C.sub.3-8-cycloalkenyl, or
aryl radicals whose ring may contain heteroatoms, preferably N or
O. Preferred heterocyclic aromatic systems are those containing at
least one nitrogen or oxygen atom. Particular preference is given
to pyridyl derivatives, very particularly preferably those which
are bound to the polymer via the 2, 4 or 6 position, or pyrrole
derivatives which are bound to the polymer via the 2 or 5 position.
These pyridyl or pyrrole derivatives very particularly preferably
have a further substituent. In the case of the pyridyl derivatives,
this is preferably in the 2, 4 or 6 position (depending on the
position via which the ring is bound to the polymer). The
substituent can be a C.sub.1-6-alkyl radical, a
C.sub.3-8-cycloalkyl radical, a C.sub.2-6-alkenyl radical, a
C.sub.3-8-cycloalkenyl radical, or an aryl radical whose ring may
contain heteroatoms, preferably N or O. A very particularly
preferred pyridyl derivative is, for example, 2,2'-bipyridyl. In
the case of the pyrrole derivatives, the further radical is
preferably located in the 2 or 5 position (depending on the
position via which the pyrrole ring is bound to the polymer).
Suitable substituents are those which have already been mentioned
in relation to the pyridyl derivatives. Very particular preference
is given to, for example, 2,2'-bipyrroles.
[0033] The anchor groups are preferably selected from among
diphenylphosphine radicals in which the phenyl groups can be
substituted or unsubstituted, pyridyl radicals which can be
substituted or unsubstituted, in particular bipyridyl radicals such
as 2,2'-bipyridyl radicals which are linked to the polymer via one
of the pyridyl groups, pyrrole radicals which can be substituted or
unsubstituted, in particular bipyrrole radicals such as
2,2'-bipyrrole radicals which are linked to the polymer via one of
the pyrrole groups, and cyclopentadienyl radicals which may, if
desired, be substituted in addition to the bond to the polymer.
[0034] Depending on the oxidation state of the transition metal and
the number of coordination sites occupied by the anchor group, the
transition metal complex may contain further ligands.
[0035] Suitable further ligands are, inter alia, uncharged ligands
L. These are generally selected from among the radicals mentioned
as anchor groups. Here, a hydrogen atom or a further substituent
preferably selected from among C.sub.1-6-alkyl,
C.sub.3-8-cycloalkyl, C.sub.2-6-alkenyl, C.sub.3-8-cycloalkenyl and
aryl radicals whose ring may contain heteroatoms, preferably N or
O, takes the place of the linkage to the polymer via a single bond,
a C.sub.2-8-alkylene group, an ether, ester or amide function or
via another group which is suitable for coupling the anchor group
to the polymer. Further suitable ligands are acetonitrile, carbon
monoxide, ethylenediamine, propylenediamine, ethylene glycol,
propylene glycol and diethylene glycol dimethyl ether
(diglyme).
[0036] Furthermore, anionic ligands X, preferably selected from
among halide anions, C.sub.1-5-alkoxy groups and C.sub.1-5-alkyl
groups, are generally present in the transition metal complex.
Halides are particularly preferred. Very particular preference is
given to chloride and bromide.
[0037] The process of the present invention is thus preferably
carried out using a transition metal complex having the formula
(III),
ML.sup.PL.sub.nX.sub.m (III)
[0038] where the symbols have the following meanings:
[0039] M is a transition metal, as defined above, very particularly
preferably selected from among Ru.sup.2+, Ru.sup.+, Mn.sup.+,
Mn.sup.4+, Cu.sup.+, Cu.sup.2+, Ni.sup.0 , Ni.sup.+, Fe.sup.2+ and
Fe.sup.+; very particularly preference is given to Ru.sup.2+ and
Ru.sup.3+;
[0040] L.sup.P is an amphiphilic polymer whose hydrophobic part as
defined above has suitable anchor groups (as defined above) for
binding the transition metal, very particularly preferably a
polyoxazoline bearing diphenylphosphine radicals as anchor
groups;
[0041] L is a further ligand as defined above, preferably selected
from among triphenyl-phosphine, in which the phenyl groups may be
substituted or unsubstituted, substituted or unsubstituted
pyridines, e.g. 2,2'-bipyridyl, substituted or unsubstituted
pyrroles, e.g. 2,2'-bipyrrole radicals;
[0042] X is a halide or a C.sub.1-5-alkoxy group or C.sub.1-5-alkyl
group as defined above; particularly preferably chloride or
bromide;
[0043] n is an integer from 0 to 4, preferably from 0 to 2;
[0044] m is from 0 to 4, preferably from 0 to 3, depending on the
valence of the metal in the first oxidation state.
[0045] In a very particularly preferred embodiment of the process
of the present invention, the transition metal complex is an
Ru.sup.2+ complex formed from a polymer built up of one hydrophilic
and one hydrophobic polyoxazoline block, where the hydrophobic
polyoxazoline block is functionalized with a diphenylphosphine
group, which complexes RuCl.sub.3 or
di-t-chlorobis((p-cymene)chlororuthenium(II).
[0046] The transition metal complexes used according to the present
invention are prepared by reaction of an appropriate transition
metal salt, preferably a halide, particularly preferably a chloride
or bromide, with the amphiphilic polymer L.sup.P bearing anchor
groups and with, if desired, further ligands L. The reaction is
carried out by methods known to those skilled in the art for
preparing transition metal complexes. For example, the desired
polymer and the desired metal salt are combined in methanolic
solution, stirred for a reaction time which depends on the
components used and the solvent is subsequently removed.
[0047] Suitable free-radically polymerizable monomers are, in
particular, ethylenically unsaturated monomers.
[0048] Suitable monomers containing at least one ethylenically
unsaturated group are, for example: olefins such as ethylene or
propylene, vinyl aromatic monomers such as styrene, divinylbenzene,
2-vinylnaphthalene and 9-vinylanthracene, substituted vinyl
aromatic monomers such as p-methylstyrene, .alpha.-methylstyrene,
o-chlorostyrene, p-chlorostyrene, 2,4-dimethylstyrene,
4-vinylbiphenyl and vinyltoluene, esters derived from vinyl alcohol
and monocarboxylic acids having from 1 to 18,carbon atoms, e.g.
vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate
and vinyl stearate, anhydrides or esters of
.alpha.,.beta.-monoethylenically unsaturated monocarboxylic and
dicarboxylic acids having from 3 to 6 carbon atoms, e.g., in
particular, acrylic acid, methacrylic acid, maleic acid, fumaric
acid and itaconic acid, with alkanols having generally from 1 to
20, preferably from 1 to 12, particularly preferably from 1 to 8
and very particularly preferably from 1 to 4, carbon atoms, for
example, in particular, methyl, ethyl, n-butyl, isobutyl,
tert-butyl and 2-ethyl-hexyl acrylates and methacrylates, dimethyl
maleate or n-butyl maleate, or the esters of the abovementioned
carboxylic acids with alkoxy compounds, for example ethylene oxide
or polyethylene oxide, e.g. ethylene oxide acrylate or
methacrylate, the nitriles of the abovementioned
.alpha.,.beta.-monoethyl- enically unsaturated carboxylic acids,
e.g. acrylonitrile and methacrylonitrile, and also
C.sub.4-8-conjugated dienes such as 1,3-butadiene and isoprene, and
N-vinyl compounds such as N-vinylpyrrolidone and
N-vinylformamide.
[0049] Possible styrene compounds are compounds of the formula IV:
1
[0050] where R' and R" are each, independently of one another, H or
C.sub.1- to C.sub.8-alkyl and n is 0, 1, 2 or 3.
[0051] In the process of the present invention, particular
preference is given to using the monomers styrene,
.alpha.-methylstyrene, divinylbenzene, vinyltoluene,
N-vinylpyrrolidone and N-vinylformamide, C.sub.1-C.sub.20-alkyl
acrylates and C.sub.1-C.sub.20-alkyl methacrylates, in particular
n-butyl acrylate, 2-ethylhexyl acrylate or methyl methacrylate, and
butadiene, also maleic acid and maleic anhydride, acrylonitrile,
glycidyl esters and (poly)alkoxylates of acrylic and methacrylic
acids, and also monomer mixtures comprising at least 85% by weight
of the abovementioned monomers or mixtures of the abovementioned
monomers, very particularly preferably styrene and methyl
methacrylate.
[0052] The present invention accordingly provides, in a preferred
embodiment, a process for preparing a polymeric reaction product in
which the free-radically polymerizable monomer is selected from the
group consisting of:
[0053] styrene compounds of the formula (IV) 2
[0054] where R' and R" are each, independently of one another, H or
C.sub.1-C.sub.8-alkyl and n is 0, 1, 2 or 3;
[0055] acrylic acid and methacrylic acid and C.sub.1-C.sub.20-alkyl
esters and C.sub.1-C.sub.100-alkyloxy esters thereof;
[0056] dienes having conjugated double bonds;
[0057] ethylenically unsaturated dicarboxylic acids and derivatives
thereof;
[0058] N-vinyl compounds;
[0059] and ethylenically unsaturated nitrile compounds.
[0060] Suitable initiators are in principle all initiators used in
ATRP catalyzed by transition metals. Preference is given to using
initiators of the formula R-Y, where Y is halogen and R is alkyl,
substituted alkyl, cycloalkyl (substituted or unsubstituted), aryl
or --CH.sub.nHal.sub.3-n, where n=0 to 2 and Hal=halogen,
preferably a bromine or chlorine atom. Preferred initiators are
selected from among ethyl 2-bromoisobutyrate, 1-phenylethyl
bromide, 1-phenylethyl chloride, p-toluenesulfonyl chloride,
benzylhydryl chloride, 1,1,1-trichloroacetone,
.alpha.,.alpha.-dichloroacetophenone, bromotrichloromethane and
carbon tetrachloride.
[0061] The ratio of transition metal complex to initiator is
generally from 1:1 to 1:3, preferably from 1:1.5 to 1:2.5,
particularly preferably from 1:1.75 to 1:2.25. The initiator
concentration selected has an influence on the molecular
weight.
[0062] The mixture preferably further comprises, in addition to the
transition metal complex, the initiator and the free-radically
polymerizable monomer, a cocatalyst in the form of a Lewis acid.
Suitable Lewis acids are generally selected from among aluminum
compounds, preferably aluminum alkoxylates; metal halides such as
ZnHal.sub.2, LiHal, where Hal is a halide, preferably Cl.sup.- or
Br.sup.-, FeCl.sub.3; BF.sub.3; acetylacetonate; conjugate organic
acids and other organic acids such as camphorsulfonic acid.
Preference is given to aluminum alkoxylates, e.g.
Al(O.sup.iPr).sub.3.
[0063] The ratio of the components transition metal complex,
initiator, Lewis acid and free-radically polymerizable monomer is
generally 0.5-2:1-3:2.5-5:100-400, preferably
0.75-1.5:1.5-2.5:3.5-4.5:150-250, particularly preferably
0.8-1.2:1.8-2.2:3.8-4.2:180-220.
[0064] The order of addition of the components used in the process
of the present invention can vary. It is possible, for example, to
introduce the transition metal complex, the initiator and, if used,
the cocatalyst in any order into the aqueous phase and subsequently
to add the monomer or monomers. It is also conceivable for the
monomer or monomers to be added gradually, either in portions or
continuously, or for different monomers to be added sequentially in
order to obtain block copolymers, in which case the respective
monomer (or monomer mixture) can again be added continuously, in
portions or all at once. However, it is also possible to introduce
the transition metal complex, any cocatalyst and the monomer or
monomers in any order into the aqueous phase and subsequently to
add the initiator. It is also conceivable for the initiator to be
added not all at once, but gradually (continuously or in portions).
Furthermore, it is possible to place the transition metal complex
and any cocatalyst in the reaction vessel initially and then to add
the initiator and the monomer or monomers all at once or gradually
(continuously or in portions).
[0065] In addition, the (reaction) mixture can further comprise a
chain transfer reagent, e.g. a mercaptan or a catalytic chain
transfer compound. Suitable compounds are known to those skilled in
the art. Suitable mercaptans are alkyl mercaptans containing at
least one --SH group, e.g. butyl mercaptan, nonyl mercaptan and
dodecyl mercaptan.
[0066] The (reaction) mixture may also further comprise additional
additives as are customarily used for modifying the properties of
the polymers, e.g. additives to alter the impact toughness of the
polymers, dyes and processing aids.
[0067] The process of the present invention is carried out in
customary reactors (e.g. stirred reactors) under reaction
conditions customary for a free-radical polymerization in an
aqueous system. In general, the process of the present invention is
carried out at temperatures above room temperature and below the
decomposition temperature of the monomers used and also below the
boiling point of the aqueous phase (depending on the respective
reaction pressure and the monomer content). Preference is given to
a temperature range from 20 to 140.degree. C., particularly
preferably from 20 to 120.degree. C., very particularly preferably
from 20 to 100.degree. C. In the process of the present invention,
excellent conversions can be achieved even at low temperatures and
in short reaction times.
[0068] The reaction pressure in the process of the present
invention is generally from 1 to 300 bar, preferably from 1 to 100
bar, particularly preferably from 1 to 20 bar.
[0069] The reaction times necessary for achieving essentially
complete conversion in the process of the present invention are
very short. The precise reaction time depends on the amount of
initiator. In general, essentially complete conversion of the
monomer or monomers used is achieved after from 0.5 to 20 hours,
preferably after from 1 to 15 hours, particularly preferably after
from 1.5 to 10 hours. For the present purposes, essentially
complete conversion means that monomer(s) can no longer be detected
by means of NMR spectroscopy.
[0070] The present invention further provides a transition metal
complex of the formula (III)
ML.sup.PL.sub.nX.sub.m (II)
[0071] where the symbols have the following meanings:
[0072] M is a transition metal, as defined above, very particularly
preferably selected from among Ru.sup.2+, Ru.sup.3+, Mn.sup.3+,
Mn.sup.4+, Cu.sup.+, Cu.sup.2+, Ni.sup.0, Ni.sup.+, Fe.sup.2+ and
Fe.sup.3+; very particularly preference is given to Ru.sup.2+ and
Ru.sup.3+;
[0073] L.sup.P is an amphiphilic polymer whose hydrophobic part as
defined above has suitable anchor groups (as defined above) for
binding the transition metal, very particularly preferably a
polyoxazoline bearing diphenylphosphine radicals as anchor
groups;
[0074] L is a further ligand as defined above, preferably selected
from among triphenylphosphine, in which the phenyl groups may be
substituted or unsubstituted, substituted or unsubstituted
pyridines, e.g. 2,2'-bipyridyl, substituted or unsubstituted
pyrroles, e.g. 2,2'-bipyrrole radicals; L is particularly
preferably triphenylphosphine in which the phenyl groups are
unsubstituted;
[0075] X is a halide or a C.sub.1-5-alkoxy group or C.sub.1-5-alkyl
group as defined above; particularly preferably chloride or
bromide;
[0076] n is an integer from 0 to 4, preferably from 0 to 2;
[0077] m is from 0 to 4, preferably from 0 to 3, depending on the
valence of the metal in the first oxidation state.
[0078] These complexes are suitable as transition metal catalysts
in ATRP in aqueous systems. These transition metal catalysts make
possible the ATRP of unsaturated monomers (suitable monomers have
been mentioned above) in high yields in short reaction times.
[0079] The present invention further provides a reaction product
which can be prepared by means of the process of the present
invention. Possible reaction products have been specified above.
The mean molecular weight (M.sub.n) is generally from 300 to 5 000
000 g/mol, preferably from 500 to 2 000 000 g/mol, particularly
preferably from 500 to 1 000 000 g/mol. The molecular weights are
determined by GPC in THF using a polystyrene standard.
[0080] These reaction products preferably have a molecular weight
distribution M.sub.w/M.sub.n measured by gel permeation
chromatography using polystyrene as standard of.ltoreq.4,
preferably.ltoreq.3, more preferably.ltoreq.2, in
particular.ltoreq.1.5 and in particular cases even.ltoreq.1.3. The
molecular weights of the reaction product can be controlled within
wide limits by selection of the ratio of monomers to free-radical
initiator.
[0081] According to the present invention, the reaction product can
be a homopolymer, e.g. polystyrene, poly(styrene-co-maleic
anhydride) or a homopolymer made up of (meth)acrylic acid, methyl
(meth)acrylates, (meth)acrylates, N-vinylpyrrolidone or olefins, or
can be a copolymer comprising blocks made up of polystyrene,
poly(styrene-co-maleic anhydride) or polymer units made up of
(meth)acrylic acid, methyl (meth)acrylate, (meth)acrylate,
N-vinylpyrrolidone or olefins.
[0082] The present invention further provides for the use of a
reaction product which can be prepared by the process of the
present invention or of a reaction product of the present invention
for producing binder formulations for coatings and other aqueous
systems.
[0083] The present invention further provides for the use of
transition metal complexes comprising an amphiphilic polymer which
is made up of a hydrophilic part and a hydrophobic part and to
whose hydrophobic part transition metals, which may optionally bear
further ligands, are bound via suitable anchor groups in a process
for preparing a reaction product under free-radical conditions in
the presence of at least one free-radically polymerizable monomer
in an aqueous medium. Suitable amphiphilic polymers, transition
metals, further ligands which may be present and monomers and
initiators have been mentioned above.
[0084] The following examples illustrate the invention.
EXAMPLES
[0085] 1. Preparation of a functionalized amphiphilic
polyoxazoline
[0086] 1.1 Monomer syntheses:
[0087] 2-Methyloxazoline (Aldrich) and 2-hexyloxazoline (Merck) are
commercially available compounds.
[0088] 1.2 Synthesis of functionalized oxazolines:
[0089] The synthesis of the functionalized polyoxazolines is
carried out by the known methods of Witte and Seeliger.
[0090] 1.3 Polymer synthesis of the macroligand (polymerization and
polymer-analogous functionalization):
[0091] 1.3.1 Synthesis of the block copolymers
[0092] Under a countercurrent of protective gas, a 25-50 mM
solution of methyl triflate in acetonitrile is placed in a reaction
vessel. The 2-methyl-2-oxazoline is added and the mixture is
stirred at a bath temperature of 80.degree. C. for 14 hours.
[0093] After cooling, the monomer(s) of the second block is/are
added and dry chlorobenzene is added if required. The mixture is
stirred at a bath temperature of 90.degree. C. for a further 14
hours.
[0094] After the reaction mixture has been cooled, an amount of dry
piperidine corresponding to 2.5 times the amount of methyl triflate
is added. The resulting mixture is stirred at room temperature for
3 hours and all volatile constituents are distilled off.
[0095] The residue is admixed with 3 g of milled and heat-dried
potassium carbonate and the amount of chloroform corresponding to
the amount of acetonitrile used above. The suspension is stirred
overnight. The insoluble constituents are separated off and the
choroform solution is precipitated in diethyl ether. The
precipitated polymer is separated from the liquid phase by
filtration and is dried.
[0096] Composition of the polymer obtained (number of repeating
units, from .sup.1H-NMR):
[0097] 37.4 2-methyloxazoline
[0098] 5.37 2-hexyloxazoline
[0099] 4.93 2-(6-(4-iodophenoxy)hexyl)-2-oxazoline calculated molar
mass: 5 857 g/mol
[0100] 1.3.2 Polymer-analogous conversion of the block copolymer
precursor into the phosphine-modified macroligand
[0101] The polymer precursor (about 2-3 g, 1 equivalent of
iodoaromatic), potassium acetate (1.44 equivalents based on the
iodoaromatic) and the palladium catalyst
(trans-di-(.mu.-acetato)-bis[o-(di-o-tolylphosphino)be-
nzyl]dipalladium(II), in a molar ratio of 1:500 to the
iodoaromatic) are weighed into the reation vessel under inert gas.
10 ml of dry acetonitrile per 1 g of polymer are added.
Diphenylphosphine (1.2 equivalents based on the iodoaromatic) is
added and the mixture is stirred at 110.degree. C. for at least 36
hours. It is subsequently cooled to room temperature. The
conversion is determined by means of .sup.1H-NMR spectroscopy.
[0102] When the conversion is quantitative, all volatile
constituents are distilled off. The residue is admixed with 1.5 g
of milled potassium carbonate and the amount of dry chloroform
corresponding to the volume of acetonitrile used above. The
suspension is stirred overnight at room temperature. All insoluble
constituents are filtered off. The polymer is purified by repeated
precipitation.
[0103] The molar mass of the macroligand calculated from the
complete conversion established by means of .sup.1H-NMR is 6 143
g/mol. Each molecule has an average of 4.93 triphenylphosphine
functions.
[0104] 2. Preparation of ruthenium complexes of the functionalized
amphiphilic polyoxazoline: complexation of ruthenium(II)
[0105] a) Starting from ruthenium(III) chloride:
[0106] {fraction (5/3)} equivalents of macroligand are used per
equivalent of ruthenium. Complexation is carried out in methanol
solution at 40.degree. C. overnight. The solvent is completely
removed and a black solid is obtained.
[0107] b) Starting from
di-.mu.-chlorobis((p-cymeme)chlororuthenium(II)):
[0108] {fraction (5/3)} equivalents of macroligand are used per
equivalent of ruthenium. Complexation is carried out in
dichloromethane solution at room temperature overnight. The solvent
is completely removed and a red solid is obtained.
[0109] 3. Polymerization experiments
[0110] 3.1 Example of an ATRP catalyzed in micelles (according to
the present invention, experiment A)
[0111] Ruthenium complex prepared as described in 2a) or 2b) (1
equivalent), initiator (CCl.sub.4) (2 equivalents), cocatalyst
(Al(OiPr).sub.3) (4 equivalents) and monomer (MMA) are
dissolved/suspended in water (about 4 ml of water per 0.1 ml of
MMA) under an argon atmosphere.
[0112] All liquids are degassed beforehand.
[0113] The solution is heated to the reaction temperature
(80.degree. C.). The reaction is terminated by sudden cooling using
a cooling bath. All volatile constituents are removed and a black
solid is obtained. This was examined by GPC (gel permeation
chromatography).
[0114] 3.2 ATRP in a standard system in toluene (comparative
experiment; experiment B)
[0115] Ruthenium catalyst RuCl.sub.2(PPh.sub.3).sub.3 (1
equivalent), initiator CCl.sub.4 (2 equivalents), cocatalyst
Al(OiPr).sub.3 (4 equivalents) and monomer MMA (200 equivalents)
are dissolved in toluene (7 ml of toluene per g of MMA) under an
argon atmosphere.
[0116] The mixture is subsequently heated to 80.degree. C. The
reaction is terminated by cooling the solution in a cooling bath.
All volatile constituents are removed and the solid obtained is
examined by GPC.
[0117] 3.3 ATRP in a standard system in toluene in the presence of
an amphiphilic poly(2-oxazoline) (comparative experiment;
experiment C)
[0118] Components used analogous to "ATRP in a standard system in
toluene" under 3.2. In addition, 150 mg of an amphiphilic
poly(2-oxazoline) were used. The solid obtained was examined by
GPC.
[0119] 3.4 System for ATRP catalyzed in micelles without ruthenium
(comparative experiment; experiment D)
[0120] Components used analogous to "ATRP catalyzed in micelles"
under 3.1. An amphiphilic poly(2-oxazoline) was used in place of
the ruthenium complex.
[0121] The table below gives the time to complete conversion of the
monomer (in hours (h)) at 80.degree. C. under various conditions
(experiments A, B, C and D), and also the mean molecular weights
(M.sub.n and M.sub.w (each in g/mol)) and the polydispersity index
(PDI; M.sub.w/M.sub.n) of the polymers obtained. The mean molecular
weights were determined by gel permeation chromatography (GPC).
1 TABLE Complete Temperature/ Mean molar mass conversion Experiment
.degree. C. M.sub.n M.sub.w PDI after t/h A1.sup.1) 80 49 000 115
000 2.35 3 A2.sup.2) 80 22 500 70 500 3.14 3 A3.sup.1) 80 113 000
329 000 2.90 3 A4.sup.2) 80 63 000 162 000 2.57 3 B 80 5 200 6 900
1.32 30 C 80 5 000 7 100 1.41 30 D 80 no polymerization no
conversion .sup.1)The ruthenium complex was prepared as described
in 2a); A1 and A3 differ in that the polymerization was carried out
at different MMA concentrations; .sup.2)The ruthenium complex was
prepared as described in 2b); A1 and A3 differ in that the
polymerization was carried out at different MMA concentrations.
[0122] The process of the present invention achieves complete
conversion at significantly shorter polymerization times compared
to a polymerization in an organic medium (experiments A and B) at
the same temperature (80.degree. C.).
[0123] The ATRP catalyzed by a metal complex in toluene is not
affected by the amphiphilic polymer (C).
[0124] In the absence of the ruthenium complex, no thermal
polymerization of MMA occurs (D).
* * * * *